Since childhood, Songoku trained by his grandfather to be a fighter. But he had to promise not to fight in school so he is considered a coward by his friends. Goku also be a dragon with a ball 4. When Goku had gone to the party with Chi Chi, Goku’s grandfather who was in the house was attacked by Picollo. When Goku returned home, he found his house destroyed and his grandfather was in a state of dying. Before he died, Grandpa Goku tells Goku to meet Master Roshi